05 f350, changed steering gear the other day and went to start the truck to bleed it out but......it started for a few seconds then died and will not start back. Now the truck has a very very slow slow crank, replaced both batteries within the past 6 months. Help!

 

Pull the belt off and see if it will crank faster, Sounds like the AC clutch pulley is locking up on you, if you loosen belt you can spin all the pulleys and see if they are free

 

I had a similar problem, it's possible your starter is on its way out. Mine was dying and wouldn't crank fast enough to build oil pressure, put a new one on and it's like starting a new truck. Maybe pull off the belt and check your accessories' pulleys and make sure they spin relatively free.